I'm fairly sure, from watching it, that Alexander Samarin's (RUS) program (from JGP Sencila Bled) is to the Mahogany soundtrack suite by Michael Masser (Diana Ross did a vocal version of it called Do You Know Where You're Going To?)
Mahogany was a movie in 1975.

Unfortunately, performers/composers of FD music are not listed there, but 2 of 3 are easily identified, thanks to youtube
Part 1: The Gulag Orkestar by Beirut, here's this music http://youtu.be/-UJX0QpkhhU
Part 2: I Don't Think About You Anymore But, I Don't Think About You Anyless by Hungry Ghosts http://youtu.be/kS9SUmAyKWM

Ms Flade said on twitter that S/S wont keep Pina Lp as they had announced but the new music remains a secret.

YES I think they had too (from discussions in their camp), V/S have raised the bar with "Violin Muse" so S/S had to change and match V/S or better, yes music is secret - lets hope its different - i think it needs to be!!

PS But 'Pina" will go down as one of the best pairs programs of all time

Does anyone know whether it is true that Takahashi's LP will be to Pagliacci?

Oh No "Unless he pulls off it off like he did with La Strada and Blues for Klook, then I would say yes, I always associated those routines with Rahkamo/Kokko and Usova/Zhulin but they are now Dai's - Pagliacci at the moment I would say is with Buttle!